Common rail fuel systems typically employ multiple fuel injectors to inject highly pressurized fuel into combustion chambers of an engine. The high-pressure fuel is supplied to the fuel injectors via a common rail or manifold that is secured along a length of the engine, and individual supply lines connected between the common rail and each of the injectors. In some configurations, flow limiters can be employed in the supply passages between the common rail and each of the fuel injectors to limit fuel leakage during catastrophic injector failure or to dampen pressure oscillations caused by normal operation of the fuel injectors.
Although functionally adequate, the common rail fuel system described above can be expensive and time consuming to fabricate. In particular, because of the high pressure of the fuel passing through the common rail, the common rail is generally made from heavy solid-stock material. The solid-stock material must be gun-drilled through its entire length to form a main bore having thick walls that can withstand the elevated pressures. In addition, each intersection of the common rail with the individual supply lines must be cross-drilled into the solid-stock material, and then treated, for example by way of autofrettage, ECM, abrasive flow, etc., to help ensure hermetic sealing of the intersections with little or no process contamination. These materials and processes used in the fabrication of the common rail increase a cost and a fabrication time of the fuel system.
One attempt to address the problems described above is disclosed in U.S. Pat. No. 6,851,412 (the '412 patent) of Jay issued on Feb. 8, 2005. Specifically, the '412 patent discloses a fuel injection system having an injector nozzle for each cylinder of an engine, and a dedicated pressure accumulator in direct connection with each nozzle. The dedicated pressure accumulators replace the common rail typical of such fuel systems. Each of the pressure accumulators is arranged at least partially within a cylinder head of the engine such that the cylinder head serves as a supporting casing for the accumulators, and extends from outside the cylinder head to the injector nozzles. Each pressure accumulator comprises a longitudinally elongated body part that defines at least two separate chambers in open fluid communication with each other and bounded by a common intermediate wall. A total volume of each pressure accumulator is at least 30 times greater than the volume of fuel injected by one injector nozzle during a single combustion stroke of the engine. The pressure accumulators fluidly communicate with each other by way of a tube system external to the cylinder head, the tube system being connected to a high pressure fuel pump driven by the engine.
Although the system of the '412 patent may reduce fuel system costs by replacing the common rail with dedicated pressure accumulators, the system may still be less than optimal. In particular, the multiple chambers within each accumulator of the '412 patent may increase a complexity of the accumulators, making the accumulators expensive and time consuming to fabricate. Further, the system of the '412 patent does not provide any way to limit fuel leakage during catastrophic injector failure or to dampen pressure oscillations caused by normal operation of an injector.
The system of the present disclosure solves one or more of the problems set forth above and/or other problems of the prior art.